AD/DO 328/33 - Cabin Pressure Control System

The instrument is structured around a small number of concrete, interlocking concepts drawn from the AD text.

• Applicability scope: The AD applies to Model 328-100 aeroplanes and, within that model, focuses on serial numbers 3005 to 3086 inclusive that do not already have a specific placard installed on the CPCS panel (Applicability; Requirement). It also notes later production aircraft incorporated the placard during manufacture (Note 1).

• Mandatory mitigant: The immediate required action is the installation of a placard on the CPCS panel in accordance with a named Dornier Service Bulletin, SB-328-21-225 (dated 27 June 1997). The AD identifies that as the default compliance obligation for affected serial numbers (Requirement).

• Alternate method of compliance (AMOC): The AD accepts a hardware modification as an optional AMOC. That is, fitting the modified Pressurisation Control Unit, P/N 22260A030201, following Dornier Service Bulletin SB-328-21-261 (dated 27 January 1999) may be used instead of the placard. The AMOC status is explicit: fitment is optional, and where fitted it permits removal of the placard (Note 2; Note 3).

• Operational hazard described: The safety trigger is an LBA advisory that "during flight above FL250, when the pressurisation control is set to the MAN mode, a pressurisation drop of approximately 1 000 ft may occur for a short time if the pressurisation control is switched back to manual mode" (Background). The AD treats placarding and/or PCU modification as the measures addressing that hazard.

• Compliance timing and legal effect: The AD sets a finite, short compliance window , 30 days after the effective date , and specifies the AD’s effective date as 19 January 2006 (Compliance). The document is issued by CASA (signature block).

• Cross-references and historical development: The AD records that earlier LBA ADs required placarding, that Dornier introduced the PCU modification in late 1999 as an AMOC, and that the modified PCU could replace the need for the placard. It refers to a specific LBA AD number (1997-242/3) (Background; Notes).

These concepts define the operator’s choices: install the placard per SB-328-21-225, or fit the modified PCU per SB-328-21-261 and then remove the placard. The AD’s text and notes identify which serial numbers are covered directly, which received the SB in production, and which later serial numbers can also be modified with the PCU as an optional AMOC (Applicability; Note 1; Note 2).

The AD identifies its target by model and serial number. The primary affected parties are the registered owners and operators of Dornier 328-100 aeroplanes described in the Applicability and Requirement sections: specifically, aeroplanes S/N 3005 to 3086 inclusive that do not already have the placard installed on the CPCS panel pursuant to the Accomplishment Instructions of Dornier Service Bulletin SB-328-21-225 (Applicability; Requirement).

Secondary affected parties include:

• Maintenance organisations and certificated engineers who must install the placard in accordance with SB-328-21-225 or fit the modified PCU per SB-328-21-261. The AD requires compliance "in accordance with" those Service Bulletins, thereby making the accomplishment instructions the technical standard for the work (Requirement; Note 2).

• Operators or owners of aircraft outside the primary S/N range who may still be interested because the AD notes that after S/N 3086 the placard "was incorporated during production" (Note 1), so later serial numbers likely already have the placard fitted. The AD also lists specific additional serial numbers (3087 to 3098 inclusive and a further discrete list) for which fitment of the modified PCU is "optional" (Note 2). Those owners have the choice to adopt the PCU modification as an AMOC.

• Regulatory and oversight bodies: CASA as issuer is the regulatory decision-maker. The AD is signed by James Coyne, Delegate of CASA (signature block). The AD also refers to the LBA’s earlier advice and LBA AD 1997-242/3 (Note 4), indicating interaction with an overseas airworthiness authority’s findings.

Who pays: the text does not state who bears the cost, but the structure and phrasing (a prescriptive AD with specific required actions tied to service bulletins) imply the aircraft owner/operator must arrange and fund either placard installation or PCU fitment within the 30-day compliance window (Requirement; Note 2; Compliance). That obligation falls on the party responsible for continuing airworthiness and compliance with ADs for the aircraft.

Who decides whether to use the AMOC: the AD treats the modified PCU as an "optional alternate method of compliance" and lists serial numbers for which it is permitted. The operator therefore has a decision to make between (a) installing the placard per SB-328-21-225 or (b) electing to adopt the PCU modification per SB-328-21-261 where their aircraft and operations make that feasible (Requirement; Note 2).

The AD lays out a compact set of duties and limited rights or choices for affected operators, maintenance organisations and owners.

Duties

• Identify applicability: Operators must determine whether their aeroplane is a Model 328-100 with S/N in the range 3005-3086 inclusive and whether the CPCS panel already has the placard installed pursuant to SB-328-21-225. If the placard is absent and the S/N is within the stated range, the AD’s requirements apply (Applicability; Requirement).

• Install placard: For covered aeroplanes without the placard, install a placard on the CPCS panel "in accordance with the Accomplishment Instructions of Dornier Service Bulletin SB-328-21-225, dated 27 June 1997" (Requirement). The AD makes the SB the technical specification to follow.

• Comply within the time limit: Perform the necessary work within 30 days after the AD’s effective date (Compliance). The AD specifies its effective date as 19 January 2006, so the applicable compliance window runs from that date (Compliance).

• Remove placard after PCU fitment: If the operator elects and completes the PCU modification per SB-328-21-261, any placards installed in accordance with SB-328-21-225 or installed during production "must be removed when the modified PCU is fitted" (Note 3).

Rights / Options

• Use of AMOC (optional): The AD explicitly allows fitment of the modified PCU (P/N 22260A030201) in accordance with SB-328-21-261 as "an optional alternate method of compliance" for the S/N 3005-3086 group (Note 2). The AD also lists additional later serial numbers for which the PCU fitment is optional (Note 2). That creates a compliance choice for owners/operators where the modification is available and practicable.

• Production placard recognition: Aircraft with S/N after 3086 "were incorporated during production" with SB-328-21-225, so such aircraft likely already meet the placard requirement and are outside the immediate installation duty (Note 1).

What the AD does not specify

• The AD does not specify a mandatory requirement to fit the modified PCU; it remains optional. It does not set out inspection or recurrent requirements beyond the initial installation or fitment. It does not itself specify penalties, nor does it detail maintenance schedule impacts or required downtime; the AD confines itself to the installation or the optional hardware fitment and the linkage between them (Requirement; Note 2; Note 3; Compliance).

Operational implications expressed as duties and choices are thus constrained to identification of affected aircraft, placard installation per SB-328-21-225 within 30 days, or electing the PCU replacement option per SB-328-21-261 and removing any placard thereafter.

The AD text supplied does not state discrete penalties, fines, or criminal sanctions within its content. It sets out prescriptive measures and a compliance deadline but does not itself contain enforcement detail or a sanctions schedule. The only enforcement-adjacent facts present in the text are:

• Issuance and authority: The Directive is issued under the authority of the Civil Aviation Safety Authority, as shown by the signature block: "James Coyne, Delegate of the Civil Aviation Safety Authority" (signature block). This identifies the regulator and the delegate who promulgated the AD.

• Compliance deadline: The AD prescribes a fixed compliance timeframe , "within 30 days after the effective date of this Directive" , and provides the AD’s effective date as 19 January 2006 (Compliance). Those elements are the practical means by which regulatory oversight and enforcement actions would be measured against operator behaviour.

What the document does not specify (in the supplied text)

• The AD does not define enforcement mechanisms, inspection regimes, or administrative penalties in the text. It does not state whether non-compliance will result in grounding, suspension of Certificates of Airworthiness, infringement notices or prosecutions. The AD also does not specify which CASA enforcement powers would be applied in the event of non-compliance.

Practical effect for operators (as implied by the AD’s form and standard practice)

• An AD by CASA is a regulatory instrument used to address an unsafe condition and to mandate corrective action. Although the supplied text does not detail enforcement steps, the existence of a short compliance window (30 days) and the specific technical instructions imply that regulatory oversight would use the compliance status of individual aircraft as a metric for continued airworthiness. The supplied AD itself, however, contains no express penalty provisions or enforcement procedures; those would sit in CASA’s broader regulatory framework, which is not reproduced or described in this AD text.

In short, the AD requires action within a short timeframe but the supply text does not enumerate specific legal penalties or the enforcement process in the event of non-compliance; it identifies the issuer (CASA) and the compliance requirement and deadline (Compliance; signature block).

The Directive cross-references and builds on international and manufacturer materials; the supplied text contains explicit ties but does not reproduce broader regulatory instruments. The interactions expressed in the AD text are:

• Reference to the Luftfahrt-Bundesamt (LBA): The AD cites LBA advice as the proximate safety trigger and explicitly refers to an LBA Airworthiness Directive number "LBA AD 1997-242/3" (Background; Note 4). That establishes an inter-jurisdictional influence: the German authority’s findings underlie the CASA AD’s rationale and remedial approach.

• Use of Dornier Service Bulletins as technical norms: Compliance is specified "in accordance with the Accomplishment Instructions of Dornier Service Bulletin SB-328-21-225, dated 27 June 1997" for the placard, and the PCU modification is tied to the "Accomplishment Instructions of SB-328-21-261, dated 27 January 1999" (Requirement; Note 2). The AD therefore makes manufacturer-issued service bulletins the technical standards for performing the required modifications. That creates an interaction between the regulatory instrument and manufacturer technical data.

• Production incorporation vs AD obligations: The AD states that for S/Ns after 3086 the SB-328-21-225 placard "was incorporated during production" (Note 1). This indicates that aircraft produced after a certain serial number already comply with the placarding requirement as a condition of original production, while earlier serial-numbered airframes require retrofit or the PCU AMOC to meet the AD’s intent.

• Alternate methods of compliance: The AD explicitly recognises an AMOC in the form of the PCU modification. By setting the modified PCU as an "optional alternate method of compliance" (Note 2), the AD interacts with the general regulatory principle that safety compliance can sometimes be achieved by an approved alternate method rather than the prescriptive fix. The AD itself defines and approves that AMOC for the listed serial numbers.

What the AD text does not do

• The supplied AD text does not quote or reproduce CASA’s broader legislative or regulatory enforcement powers, nor does it describe how CASA’s AD enforcement interacts with Civil Aviation Regulations or other legislation. The AD also does not describe how compliance records are to be logged, or how acceptance of the AMOC is to be evidenced beyond following the referenced service bulletins.

• The AD does not create or modify airworthiness certification standards; rather, it prescribes a corrective action that affects continuing airworthiness. Any legal effect beyond the prescriptive requirement will depend on CASA’s regulatory processes and documentation practice, which are not detailed in this document.

In sum, within the supplied text the AD interacts with (a) LBA findings and an LBA AD by reference, and (b) manufacturer service bulletins SB-328-21-225 and SB-328-21-261 by making them the technical accomplishment instructions for the required or alternate actions. The AD also distinguishes production-conforming aircraft (S/N > 3086) from retrofit cases.

The supplied AD text itself provides a compact historical record relevant to the remedial measures and their provenance. The key temporal facts recorded in the AD are:

• Dornier Service Bulletin SB-328-21-225 dated 27 June 1997: The placard instruction derives from that Service Bulletin (Requirement).

• LBA AD and earlier LBA action: The text states "Initially, earlier issues of the LBA Airworthiness Directive required placarding of the CPCS panel on aeroplanes S/N 3005 to 3086," indicating the placard requirement stems from earlier LBA directives (Background). The AD also explicitly cites LBA AD 1997-242/3 (Note 4).

• Dornier Service Bulletin SB-328-21-261 dated 27 January 1999: The text records that Dornier introduced a modified PCU and published SB-328-21-261 in late 1999, offering the modified PCU as an AMOC to the placarding requirement (Requirement; Note 2; Background). The AD states that the AMOC was introduced "in late 1999" in the LBA’s process, and the SB is dated 27 January 1999.

• CASA issuance and dates: The Directive is signed on 1 December 2005 by the CASA delegate (signature block). The AD becomes effective on 19 January 2006 and requires compliance within 30 days after that effective date (Compliance). Those dates are the issuance, effective, and compliance milestones for the CASA AD.

• Production incorporation: The AD records that for serial numbers after 3086, "SB-328-21-225 was incorporated during production" (Note 1). This is a production-line change noted in the AD.

• Background explanatory paragraph: The AD documents the sequence that LBA initially required placarding, later introduced the modified PCU as an AMOC, allowed that AMOC to be applied to aircraft already placarded, and permitted removal of the placard after PCU installation. The AD states that Notes 2 and 3 reflect this history (Background).

The AD does not contain a formal amendment log or a record of subsequent modifications to the AD text itself beyond those historical facts. There is no text indicating later CASA amendments to AD/DO 328/33 in the supplied document. The amendment history recorded is therefore effectively the progression: initial LBA placarding requirement in the late 1990s, Dornier SB-328-21-261 (1999) as a hardware AMOC, production incorporation for later serials, and the CASA AD issuance in December 2005 effective January 2006.

The supplied AD text does not record any litigation, disputes, appeals, or case law arising from AD/DO 328/33. The document contains no references to judicial proceedings or administrative appeals in relation to this Directive.

What the AD does record relevant to potential disputes or traceability are administrative reference points and dates that would be relevant in any future compliance or enforcement dispute:

• The AD’s issuer and signatory: "James Coyne, Delegate of the Civil Aviation Safety Authority" (signature block) is the named CASA delegate who issued this Directive on 1 December 2005.

• The effective date and compliance window: Effective 19 January 2006 with compliance required within 30 days (Compliance). Those dates would be material to any compliance-status inquiry or challenge.

• Technical documents cited: Dornier Service Bulletins SB-328-21-225 (27 June 1997) and SB-328-21-261 (27 January 1999) are the documents the AD requires or uses as alternate compliance methods (Requirement; Note 2). LBA AD 1997-242/3 is referenced (Note 4). Any litigation or review would be likely to engage those documents and their content.

Because the supplied text contains no litigation history, readers should treat the AD as a regulatory instrument whose enforcement and any disputes would be handled through CASA’s established regulatory and legal channels; those channels and any related case law are not reproduced in this AD text.

The AD text contains several features and wording choices that operational staff, maintenance planners and compliance officers should note carefully to avoid common implementation errors.

• Serial number boundary and applicability nuance: The AD applies to Model 328-100 aeroplanes S/N 3005 to 3086 inclusive that do not have the SB-328-21-225 placard installed. Aircraft with S/N after 3086 "had SB-328-21-225 incorporated during production" (Note 1). Practically, you must verify both the serial number and the physical presence of the placard installed "in accordance with" SB-328-21-225 , absence of a placard, even on a later S/N, could be material. The AD makes the presence or absence of the placard a determinative condition (Applicability; Note 1).

• Short compliance window: The AD requires compliance "within 30 days after the effective date" and the effective date is 19 January 2006 (Compliance). That creates a tight planning window for operators to arrange the work, procure parts, and schedule maintenance slots. Treat the 30-day period as the mandatory window for initial compliance planning.

• AMOC is optional, not automatic: Fitment of the modified PCU (P/N 22260A030201) per SB-328-21-261 is expressly "an optional alternate method of compliance" for S/N 3005-3086 and optional for a discrete set of later serial numbers (Note 2). That means operators are not required to fit the PCU; however, if they do fit it, the AD requires removal of the placard (Note 3). Selecting the AMOC therefore creates a follow-up duty to remove the placard.

• Serial number list for AMOC beyond 3086: Note 2 lists particular later serial numbers where the modified PCU is optional (3087 to 3098 inclusive, plus specific later S/Ns: 3100, 3101, 3104, 3106, 3107, 3109, 3110, 3112, 3113, 3115, 3117 and 3119). That list is non-contiguous; check each S/N individually rather than assume a continuous range (Note 2).

• Placard removal requirement: The AD explicitly states "Placards installed in accordance with SB-328-21-225 or during production must be removed when the modified PCU is fitted" (Note 3). Operators fitting the PCU must therefore ensure documentation records the placard removal, and maintenance records are updated.

• Cross-reference discrepancy in background paragraph: The background narrative refers to aircraft "placarded in accordance with SB-328-21-255" at one point, while the Requirement and other notes consistently refer to SB-328-21-225. That inconsistency appears in the AD’s background paragraph. Practitioners should follow the Requirement text and the specific SB references given elsewhere (Requirement; Background). When in doubt, confirm the correct SB number (the Requirement and the boxed Applicability/Requirement specify SB-328-21-225).

• Technical compliance via Accomplishment Instructions: The AD requires work to be done "in accordance with the Accomplishment Instructions" of specific Dornier Service Bulletins (Requirement; Note 2). Using different or abbreviated methods that do not follow the Accomplishment Instructions could fail to meet the AD unless the operator obtains formal approval for a different method.

• Recordkeeping and evidence: While the AD does not describe the required paperwork, the small but precise linkage between placard presence, SB conformity, and PCU P/N requires maintenance logs that document the SB used, the PCU P/N if changed, and the placard removal or installation. The AD’s compliance check will be based on those physical and documentary facts.

• LBA reference: The AD refers to LBA AD 1997-242/3 (Note 4). Operators with international maintenance or registry issues should be aware of this cross-jurisdictional origin of the safety concern.

• No explicit mention of inspections or recurrent requirements: The AD is narrow in scope and prescriptive in the immediate remedial actions; it does not introduce inspection intervals or recurrent checks in the supplied text. Do not assume further surveillance obligations are created by the AD aside from initial compliance, unless CASA has issued additional material elsewhere.

In short, verify exactly which aircraft are affected, follow the specified Service Bulletin Accomplishment Instructions, be aware of the short compliance timeline, log placard installations/removals alongside any PCU replacement P/N, and exercise caution in reading the background text where a Service Bulletin number appears inconsistent.

The AD gives an unambiguous compliance pathway and an alternate route. Follow these steps, in order and with documentary evidence in the aircraft maintenance records.

1. Identify applicability and current configuration

   • Confirm the aircraft model is Dornier 328-100.
   • Confirm the serial number (S/N). If S/N is between 3005 and 3086 inclusive, proceed to step 2. If S/N is after 3086, check whether the placard was incorporated during production (Note 1). If S/N matches one of the later serial numbers listed in Note 2 and you intend to fit the modified PCU, those aircraft are eligible for the AMOC (Note 2).

2. Inspect physical CPCS panel

   • Check whether a placard exists on the Cabin Pressure Control System (CPCS) panel and whether the placard was installed "in accordance with the Accomplishment Instructions of Dornier Service Bulletin SB-328-21-225." If the placard is present and complies with SB-328-21-225 (or was installed during production for later S/Ns), no placard installation action is required (Applicability; Note 1).

3. If placard is absent and S/N 3005-3086 inclusive, install placard

   • Within 30 days after the AD’s effective date (effective 19 January 2006), install the placard on the CPCS panel "in accordance with the Accomplishment Instructions of Dornier Service Bulletin SB-328-21-225, dated 27 June 1997" (Requirement; Compliance).
   • Ensure maintenance records identify the SB used and include the date of installation and the technician or organisation performing the work as evidence of compliance.

4. Consider optional AMOC via PCU replacement

   • As an alternative to the placard, elect to fit the modified Pressurisation Control Unit (PCU), P/N 22260A030201, "in accordance with the Accomplishment Instructions of SB-328-21-261, dated 27 January 1999" (Note 2).
   • Confirm your S/N is within the AD’s AMOC permission set. The AD lists S/N 3005-3086 inclusive as eligible for the AMOC; it also lists additional later S/Ns for which the PCU fitment is optional (3087-3098 inclusive and specific later S/Ns) (Note 2).

5. If fitting the PCU, remove any placard

   • If you fit the modified PCU, remove any placards installed in accordance with SB-328-21-225 or installed during production as required by the AD (Note 3). Record the removal in maintenance records, noting the PCU P/N installed and the SB compliance.

6. Use the Accomplishment Instructions exactly

   • Perform work "in accordance with" the respective Service Bulletin Accomplishment Instructions. The AD ties compliance to the Accomplishment Instructions of SB-328-21-225 for the placard and SB-328-21-261 for the PCU fitment (Requirement; Note 2). Deviations from those instructions may require separate approval.

7. Recordkeeping and proof of compliance

   • Maintain documentation of the placard installation or PCU fitment, the SB and its date used for the accomplishment instructions, serial numbers and part numbers (notably PCU P/N 22260A030201 if fitted), and the dates of the work. Although the AD text does not spell out a returns process, these records are the evidentiary basis of compliance.

8. Plan for operational impact

   • The AD’s 30-day compliance window requires scheduling of maintenance early. Ensure maintenance providers understand the exact SB instructions, availability of the PCU P/N if opting for AMOC, and the placard installation specifics.

9. Note cross-references and provenance

   • The AD cites LBA advice and LBA AD 1997-242/3 (Note 4). If your aircraft has multi-jurisdictional registry or maintenance arrangements, ensure the documentation satisfies both CASA and any other competent authority oversight requirements.

10. Where there is uncertainty

    • If there is any ambiguity regarding which SB is referenced (see the background paragraph discrepancy that refers to SB-328-21-255 at one point), rely on the Requirement which specifies SB-328-21-225, and confirm with CASA or the relevant maintenance authority if necessary (Requirement; Background).

The practical conclusion of compliance is either that the CPCS panel bears the required placard installed per SB-328-21-225, or that the PCU P/N 22260A030201 has been fitted per SB-328-21-261 and any placard has been removed, with supporting maintenance documentation recorded and filed within the operator’s continuing airworthiness records.